Some printing technologies employ a special substrate coating or a priming treatment prior to the application of ink or toner. Generally this kind of treatment is performed at a stage when a print medium or substrate is fed from a roll, e.g. before cutting operations. Applying a priming treatment in this manner helps the treatment process to be stable and continuous. However, there are cases when a priming treatment is better applied to cut sheets of print media or substrate. For example, this may be the case for thick substrates or for cases where a priming fluid is applied shortly before ink application for better ink adhesion. There are also cases where a print medium or substrate or other print target may vary in shape and/or size. For example, in a printing system with a variable cut sheet size, a substrate coating may be applied to varying sizes of sheet.